Use Plug.Conn.send_resp/3 in Module attributes section of Getting Started (elixir-lang#1293)

Author: irisTa56

getting-started/module-attributes.markdown

@@ -137,7 +137,7 @@ defmodule MyPlug do
   end
 
   def send_ok(conn, _opts) do
-    send(conn, 200, "ok")
+    send_resp(conn, 200, "ok")
   end
 end